Solid, high-energy compositions, such as propellants for rocket motors, gasifier charges, explosive charges or the like, generally comprise particulate solids, including fuel material and oxidizers, dispersed in an elastomeric binder which spatially immobilizes the solids. The high-energy composition frequently contains nitrate ester plasticizers which enhance the elastomeric properties of the binder and furthermore enhance the energy value of the high-energy composition.
Among the common types of propellant binders are poly(caprolactone)-based binders in which poly(caprolactone) polymers are cured with poly(isocyanates). Poly(caprolactone) polymers exhibit excellent miscibility with nitrate ester plasticizers and are therefore especially suitable for propellant formulations which include nitrate ester plasticizers. Poly(caprolactone) binders have thermal and mechanical properties suitable for a wide variety of propellant applications.
Poly(caprolactone) polymers (PCP) presently used to prepare binders in propellant formulations generally have molecular weights in the 2000 to 3000 range and generally have functionalities of 2. Curatives are poly(isocyanate) compounds of multiple functionality.
Advanced rocket motor designs continue to demand additional mechanical property performance from propellant binder systems. Such mechanical performance requirements are not achieved by presently used poly(caprolactone) binders. Thus, there exists a need for novel poly(caprolactone) binders having improved mechanical properties, particularly improved stress and strain capabilities.